The mighty Sir William Prescott engine is the world’s largest working triple-expansion steam engine. For over half a century it pumped 19 million gallons of water every day for the people of London. You can see it in action at our next steaming weekend on the 18th & 19th May. #steam #steamengines #massive #massiveengineering #london #hiddenlondon #museum #vintage #heritage #titanic | Kempton Steam Museum